Micronutrients, Frailty, and Cognitive Impairment: Design and Preliminary Results from the CogLife 2.0 Study.

Background: Among preventive strategies against dementia, nutrition is considered a powerful one and the recently established "nutritional cognitive neuroscience of aging" is a highly active research field. Objective: The present study was designed to deeply characterize older adults across the continuum from cognitive integrity to mild cognitive impairment (MCI) and better elucidate the prognostic role of lipophilic micronutrients within their lipidomic signature. Methods: 123 participants older than 65 years across the continuum from cognitive integrity to MCI were included [49 with subjective cognitive impairment, 29 women, 72.5±5.4 years, 26 MCI, 9 women, 74.5±5.8 years and 50 without cognitive impairment, 21 women, 70.8±4.3 years]. All participants underwent neuropsychological and nutritional examination as well as comprehensive geriatric assessment with calculation of the Multidimensional Prognostic Index (MPI) as a proxy of frailty and biological age and blood withdrawal for the analyses of lipophilic micronutrients, metabolomics and oxylipidomics. One year after the evaluation, same tests are ongoing. Results: After adjustment for age, sex, daily fruit and vegetable intake and cholesterol, we found a significant positive correlation between lutein and the number of correct words in category fluency (p = 0.016). Conclusions: This result supports the importance of carotenoids as robust biomarkers of cognitive performance independent of the nutritional status and frailty of the participants, as the entire present study collective was robust (MPI 0-0.33). The complete analyses of the metabolome and the oxylipidome will hopefully shed light on the metabolic and prognostic signature of cognitive decline in the rapidly growing population at risk of frailty.

Effects of carotenoids on mitochondrial dysfunction.

Oxidative stress, an imbalance between pro-oxidant and antioxidant status, favouring the pro-oxidant state is a result of increased production of reactive oxygen species (ROS) or inadequate antioxidant protection. ROS are produced through several mechanisms in cells including during mitochondrial oxidative phosphorylation. Increased mitochondrial-derived ROS are associated with mitochondrial dysfunction, an early event in age-related diseases such as Alzheimer's diseases (ADs) and in metabolic disorders including diabetes. AD post-mortem investigations of affected brain regions have shown the accumulation of oxidative damage to macromolecules, and oxidative stress has been considered an important contributor to disease pathology. An increase in oxidative stress, which leads to increased levels of superoxide, hydrogen peroxide and other ROS in a potentially vicious cycle is both causative and a consequence of mitochondrial dysfunction. Mitochondrial dysfunction may be ameliorated by molecules with antioxidant capacities that accumulate in mitochondria such as carotenoids. However, the role of carotenoids in mitigating mitochondrial dysfunction is not fully understood. A better understanding of the role of antioxidants in mitochondrial function is a promising lead towards the development of novel and effective treatment strategies for age-related diseases. This review evaluates and summarises some of the latest developments and insights into the effects of carotenoids on mitochondrial dysfunction with a focus on the antioxidant properties of carotenoids. The mitochondria-protective role of carotenoids may be key in therapeutic strategies and targeting the mitochondria ROS is emerging in drug development for age-related diseases.